On April 29, 1996, three cases of tetrodotoxin poisoning
occurred among chefs in California who shared contaminated fugu
(puffer fish) brought from Japan by a co-worker as a prepackaged,
ready-to-eat product. The quantity eaten by each person was
minimal, ranging from approximately 1/4 to 1 1/2 oz. Onset of
symptoms began approximately 3-20 minutes after ingestion, and all
three persons were transported by ambulance to a local emergency
department (ED). This report summarizes the investigation of these
cases by the San Diego Department of Environmental Health (SDEH)
and the Food and Drug Administration (FDA).
Case Reports

Case 1. A 23-year-old man ate a piece of fugu "the size of a
quarter" (approximately 1/4 oz). Approximately 10-15 minutes later,
he had onset of tingling in his mouth and lips followed by
dizziness, fatigue, headache, a constricting feeling in his throat,
difficulty speaking, tightness in his upper chest, facial flushing,
shaking, nausea, and vomiting. His legs weakened, and he collapsed.
On examination in the ED, his blood pressure was 150/90 mmHg; heart
rate, 117 beats per minute; respiratory rate, 22 per minute;
temperature, 99.3 F (37.4 C); and oxygen saturation, 99% on room
air.

Case 2. A 32-year-old man ate three bites of fugu
(approximately 1 1/2 oz) over 2-3 minutes. While eating his third
bite, he noticed tingling in his tongue and right side of his mouth
followed by a "light feeling," anxiety, and "thoughts of dying." He
felt weak and collapsed. At the ED, his blood pressure was 167/125
mmHg; heart rate, 112 beats per minute; respiratory rate, 20 per
minute; and oxygen saturation, 96% on room air.

Case 3. A 39-year-old man ate approximately 1/4 oz of fugu
after eating a full meal. Approximately 20 minutes after eating the
fugu, he had onset of dizziness and mild chest tightness. At the
ED, his blood pressure was 129/75 mmHg; heart rate, 84 beats per
minute; respiratory rate, 22 per minute; temperature, 97.2 F (36.2
C); and oxygen saturation, 97% on room air.
Diagnosis and Treatment

A presumptive diagnosis of tetrodotoxin poisoning in all three
men was based on clinical presentation in the ED and the history of
recent consumption of fugu. All were treated with intravenous
hydration, gastric lavage, and activated charcoal. Symptoms
gradually resolved, and the men were discharged the following day
with no residual symptoms.
Follow-Up Investigation

The chef who brought the fugu from Japan failed to declare
this item through customs. The remaining fugu was obtained for
toxin analysis at FDA. SDEH contacted health authorities in Japan
and relayed the product label information for identification of the
product manufacturer to assist in their local follow-up
investigation.

Editorial Note

Editorial Note: The order Tetraodontoidea includes ocean sunfishes,
porcupine fishes, and fugu, which are among the most poisonous of
all marine life (1). These species inhabit the shallow waters of
the temperate and tropical zones and can be exported from China,
Japan, Mexico, the Philippines, and Taiwan. The liver, gonads,
intestines, and skin of these fish contain tetrodotoxin, a powerful
neurotoxin that can cause death in approximately 60% of persons who
ingest it (2). Other animals (e.g., California newt and the eastern
salamander) also possess tetrodotoxin in lethal quantities (3)
(Table_1).

Tetrodotoxin is heat-stable and blocks sodium conductance and
neuronal transmission in skeletal muscles. Paresthesias begin 10-45
minutes after ingestion, usually as tingling of the tongue and
inner surface of the mouth. Other common symptoms include vomiting,
lightheadedness, dizziness, feelings of doom, and weakness. An
ascending paralysis develops, and death can occur within 6-24
hours, secondary to respiratory muscle paralysis. Other
manifestations include salivation, muscle twitching, diaphoresis,
pleuritic chest pain, dysphagia, aphonia, and convulsions. Severe
poisoning is indicated by hypotension, bradycardia, depressed
corneal reflexes, and fixed dilated pupils. Diagnosis is based on
clinical symptoms and a history of ingestion. Treatment is
supportive, and there is no specific antitoxin (6). Despite the
high death rate associated with tetrodotoxin poisoning, the three
persons described in this report survived probably because of the
small amount of toxin ingested and rapid stomach evacuation by the
ED.

Although personal importation of fugu into the United States
is prohibited, FDA has permitted fugu to be imported and served in
Japanese restaurants by certified fugu chefs on special occasions.
A cooperative agreement with the Japanese Ministry of Health and
Welfare ensures fugu is properly processed and certified safe for
consumption before export by the government of Japan. If cleaned
and dressed properly, the fugu flesh or musculature is edible and
considered a delicacy by some persons in Japan, who may pay the
equivalent of $400 U.S. for one meal. Despite careful preparation,
fugu remains a common cause of fatal food poisoning in Japan,
accounting for approximately 50 deaths annually (7).

Although arriving travelers are required to declare all food
products brought into the United States, control measures rely
primarily on the traveler. Other foodborne outbreaks in the United
States have occurred after consumption of illegally imported food
products (8). Persons who travel to countries where fugu is served
should be aware of the potential risk of eating this fish.

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